carbohydrates because carbohydrates in swine wastewater are
mainly composed of humic substances. Humic substances such
as humic acids (HA) or fulvic acids (FA) in swine manure are colloidal
chemicals, and are operationally defined by their solubility
and/or molecular size. Because organic matter in swine manure
contains more humified products, it is important to characterize
humic substances in swine wastewater. Kim et al. [28] reported
that humic natural organic matter (NOM) such as HA and FA causes
accumulated adsorption of hydrophobic solutes on the ion
exchange membrane surfaces. This implies that the replacement
schedule of an ion exchange membrane can shorten unless swine
wastewater was irradiated by an electron beam irradiation in the
field. The variation of SCOD removal with an OLR is shown in
Fig. 2b. The average SCOD removal efficiencies at doses of 0 kGy,
20 kGy, 50 kGy, 75 kGy and 100 kGy were 74.4%, 82.5%, 85.2%,
85.8% and 83.7%, respectively. In this study, with increasing dose,
the average influent SCOD concentration increased after an electron
beam irradiation (data not shown). This shows that the influent
in swine wastewater was solubilized in the range between
20 kGy and 75 kGy.